N, n-disubstituted isopicramic acid salts for dyeing human hair



United States Patent 3,344,031 N,N-DISUBSTITUTED ISOPICRAMIC ACID SALTS FOR DYEING HUMAN HAR Jerzy .iosef Bartoszewicz, Heston, England, assignor to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Filed Dec. 11, 1963, Ser. No. 329,868 Claims priority, application Great Britain, Dec. 21, 1962, 48,481/ 62 16 Claims. (Cl. 167-88) The present invention relates to processes for the direct dyeing of keratinous fibres, such as hair and fur, and to compositions for use in such processes. The invention further relates to novel direct dyes suitable for use in such processes and compositions.

In the field of direct dyes there has long been recognised a need for the improvement of hair colourants which can produce natural colour effects, especially brown, on heads having in excess of white hair. To achieve these natural colour eiiects it is necessary to employ blue to violet dyes free or substantially free of a red tone. There are extremely few direct nitro dyes which fulfill these requirements. Examples of those which are known are given in British patent specification 74l,334.

However, these direct dyes have the disadvantage that they eiiieiently cover up to 5060% white hair only under conditions of high alkalinity (such as pH about 11) which have an adverse eifect on hair condition.

It is an object of the present invention to provide an improved process of dyeing keratinous fibres, especially live hair, which employs dyes capable of dyeing hair a blue to violet shade free or substantially free of any red tone and which can be applied to the hair with good uptake whilst avoiding conditions of high alkalinity.

According to the present invention there is provided a process of dyeing keratinous fibres, which comprises applying thereto an aqueous solution having a pH of from 2 to 9 of a compound of the general formula:

where:

M is a hydrogen, an alkali or alkaline-earth metal, or

an ammonium or substituted-ammonium radical;

R is an alkyl group or a hydroxylalkyl group having up to 4 carbon atoms; and

R is a hydroxyalkyl group having up to 4 carbon atoms.

Examples of suitable substitutedammonium radicals for the group M are ammonium radicals in which one or more of the hydrogen atoms is substituted by an alkyl group having up to 6 carbon atoms or by a hydroxyalkyl or aminoalkyl group having up to 4 carbon atoms.

Examples of suitable hydroxyalkyl groups for R and R are the groups -CH CH OH, 'CH CH CH OH, CH CH(OH)CH and -CH CH(OH)CH OH. Of these groups, the preferred one is the Z-hydroxyethyl group.

As specific examples of metals for the group M in the above formula are mentioned sodium, potassium, and calcium, and as examples of substituted-ammonium radicals for M are mentioned those derived from mono-, di-, and tri-ethanolamine or isopropanolamine, and those derived from mono-, di-, and tri-methylamine, ethylamine and isobutylamine.

3,344,3l Federated Sept. 26, 1967 It is preferred to employ in the process of the invention the sodium, potassium, ammonium and substitutedammonium salts of N,N-di-(2-hydroxyethyl)-isopicramic acid.

The dyes employed in the process of the invention produce on keratinous fibres deep blue-violet to violet dull shades free or substantially free of a red tone which is rare for a nitro dye.

The invention also provides a composition for the direct dyeing of keratinous fibres, especially living hair, containing a dye of the above-mentioned general formula in aqueous solution having a pH of from 2 to 9, preferably having a pH of from 3.5 to 8; best results are obtained with solution having a pH of from 6.5 to 7.5. Dyes of the above-mentioned general formula may be used with other suitable nitro dyes to produce blonde, brown and grey shades. When the above blue-violet to violet dyes are used in conjunction with a yellow dye as in, for example, the formulation of a composition for producing brown or 'blonde shades, the yellow dye is preferably 2-nitro-N-methyl-N-acetyl-p-amino-phenol or N- methyl-N-acetyl-isopicramic acid or an alkali metal, alkaline-earth metal, ammonium or substituted-ammonium salt thereof; in the case of a substituted-ammonium salt, the substituted-ammonium radical may be one as given above for the group M in the above general formula. Since these yellow dyes have a similar chemical structure to that of the blue-violet to violet dyes of the above general formula, the combination possesses useful properties. For instance, selectivity on certain hairs is minimised and also the fastness of the colour of the dyed fibre is very good. The combination also has good stability on storage of the composition.

The invention further provides new direct dyes, for use in the above process and composition, having the general formula OzN NO:

R1 I N where M is an alkali or alkaline-earth metal, an ammonium or substituted-ammonium radical; and R and R have the above meanings.

Example 1 .Preparation of N,N-di-(2-hydr0vcyethyl)- isopicramic acid potassium salt A 5 litre three-neck flask equipped with an automatic stirrer and attached to a water-bath and a condenser was used. 132 g. of the ammonium salt of isopicramic acid were added to 400 ml. of methyl alcohol, 96 ml. of water and 540 ml. of 2-chloro-ethanol. The temperature of the water-bath was raised to C. 92 g. of potassium hydroxide dissolved in 360 ml. of water were added over a period of one hour. The temperature of the water-bath was then gradually increased over a period of half an hour and the reaction mixture was kept refluxing for 2 /2 hours at 86 C. After cooling to 70 C., 144 ml. of 2- chloro-ethanol were added followed by 72 g. of potassium hydroxide in 144 ml. of water during 20 minutes. The reaction mixture was refluxed for a further 1% hours. It was then cooled for 40 minutes and filtered. The deep violet filtrate was then poured into 3 litres of water and made acid to Congo Red paper with 90 ml. of concen trated hydrochloric acid. It was left overnight for the N,N-di-(2-hydroxyethy1)-isopicramic acid to crystallise out and on filtration 112 g. of moist dyestuif cake were produced.

The potassium salt of N,N-di-(2-hydroxyethyl)-isopicramic acid was then produced as follows. The welldrained dyestuff cake previously produced was mixed to a smooth paste with ml. of isopropyl alcohol and with a solution of g. of potassium carbonate in 20 g. of water. Evolution of carbon dioxide took place. The dyestuff was then dried at 50-60 C. in a vacuum oven under a reduced pressure (60-70 cm. Hg). The yield was 93 g. of soft bronzy lumps which were easy to grind.

The N,N-di-(2-hydroxyethyl)-isopicramic acid obtained (such as N-methyl-isopicramic acid) instead of from a salt of isopicramic acid.

The alkaline-earth metal salts of, for instance, N,N-di- (Z-hydroxyethyl)-isopieramic acid, can be prepared by reacting this acid with a suitable alkaline-earth metal compound, such as calcium carbonate. Further, the alkanolammonium and aminoalkyl-ammonium salts of N,N-di- (Z-hydroxyethyl)-isopicramic acid may be prepared by neutralising this acid with an alkanolamine, such as mono-, dior tri-ethanolamine or isopropanolamine, or an alkylene diamine, for example diethylene diamine.

The invention is further illustrated by the following Examples 4 to 7 of compositions for the direct dyeing of hair. In these examples the percentages are percentages by Weight.

Examples, Percent Potassium salt of N,N-di-(2-hydroxyethyl)- isopieramie acid 0. 3 Ammonium salt of N ,N-di-(2-hydroxyethyl)- lsopicra-mie acid 0. 3 0. 8 1. 2 N-methyl-N-acetyl-isopieramic acid 0. l5 0. 45 0. 65 Mononitro derivatives of 4-amino-salicylic id 0.03 Glycerol 5 Formamide 5 5 5 Lauryl polyethylene glycol 5 5 5 5 Perfume 0. 5 0. 5 0. 5 0. 5 Thickener [Carbopol 934 paste (a 2% wjw.

aqueous dispersion of a earboxylic-substituted vinyl polymer neutralised with ammonium hydroxide)] 30 ater to 100 to 100 to 100 to 100 as described above, on recrystallisation from boiling water gave the pure dyestutf in the form of lustrous reddish scales of melting point 144-146 C. Although this compound and its aqueous solution is reddish in colour, it has been surprising to find that it dyes hair a violet shade.

Example 2.-Preparation of N,N-di-(2-hydroxyethyl)- picramic acid ammonium salt The preparation of N,N-di-(2-hydroxyethyl) -isopicramic acid was first carried out as described in Example 1.

The dyestufif cake obtained was mixed to a smooth paste with a solution of 1 volume of ammonia (specific gravity 0.88) in 4 volumes of methyl alcohol. The dyestuif paste was then dried at -60 C. in a vacuum oven at reduced pressure (60-70 cm. Hg) and ground in a mortar. The yield was similar to that obtained in Example 1. On recrystallisation from boiling water the pure dyestuff was obtained in the form of blackish bronzy prisms which melted at 165-167 C. With decomposition.

Example 3.Preparation of N,N-a'i-(Z-hydroswethyl)- isopicramic acid di-iso-butylamine salt The preparation of N,N-di-(2-hydroxyethyl)-isopicramic acid was first carried out as described in Example 1.

18 g. of this compound (dry) were mixed with 7.5 g. of di-iso-butylamine ((CH CH-CH NH dissolved in 10 ml. of methyl alcohol. The thin paste became considerably thicker on stirring and it was dried at 40-50 C. in a vacuum oven at reduced pressure (60-70 cm. Hg). The yield was 25 g. On recrystallisation from boiling water the pure dyestulf was obtained in the form of violetish-brown crystals which melted at 122-124 C. with decomposition.

The dyestuif produced in this way had lower solubility in water but had more afiinity for hair and other keratinous fibres and when dyed from aqueous shampoo base produced darker shades of blue-violet than the potassium and ammonium salts.

Compounds having an alkyl group attached to the amino nitrogen atom can be prepared in a similar manner to that described in Example 1 by starting from a salt, for example the ammonium salt, of N-alkyl-isopicramic acid The following procedure was adopted in preparing the above compositions. The dyestuffs, glycerol or formamide, lauryl polyethylene glycol and water were mixed and heated to 70-75 C. A 2% w./w. aqueous dispersion of Carbopol 934 was partly neutralised with ammonium hydroxide (specific gravity 0.88) to a pH of 7.0 to 7.5 and perfume mixed in. The mixture containing the dyestuifs Was then stirred slowly into the Carbopol 934 paste and stirring continued until a homogeneous paste was obtained. Where necessary the pH of the paste was adjusted to 6.5-7.0 by the addition of 10% lactic acid or 10% monoethanolamine.

The above compositions gave (on heads with 30-70% White hair) natural shades with acceptable fastness to shampooing, light and perspiration. They were compatible with the effects produced by cold permanent Waving and were free from scalp staining and had a good conditioning efiect on the hair. Example 4 gave a light grey shade; Example 5 a blonde shade; Example 6 a light brown shade; and Example 7 a medium brown shade.

As a result of salon tests, a pH of 6.5 to 7.0 was found to be the optimum value for the colour uptake and for imparting a good conditioning effect to the hair. When the pH of the colourant paste was lower than 6 a more yellowish shade was obtained. When the pH was higher than 7.0 more violetish-brown shades were produced. The control of the pH value of the colourant is therefore important. A viscosity of 400 to 800 centipoises gave the best results in colour uptake and permitted the easiest application.

The compositions can be applied with a sponge or a brush or from an applicator to either dry or previously shampooed and towel-dried hair.

The dyestuffs used in the process of this invention have a number of important advantages over those dyestuffs in 'Which in the above formula R or R or both of these groups are hydrogen atoms. Apart from being considerably bluer, which makes the dyestuffs better for the formulation of colourants for producing blonde and brown shades, the dyestuffs used in this invention give shades having superior fastness to acids (and therefore to perspiration), and to light and permanent waving.

The following experiment was carried out to compare the colour change of the dyestufis isopicramic acid, N- methyl-isopicramic acid and N,N-di-(2-hydroxyethyl)- isopicramic acid under the influence of different pH. Aqueous solutions of these dyestuffs were used as indicators when 0.1 N solutions of NaOH and Na CO were titrated with 0.1 N HCl. Methyl Orange indicator was used in comparison experiments. The pH value at the colour change was confirmed by taking readings on an electric pH-meter. Colour change occurred at the following pH values:

Dyestuff: pH Isopicramic acid 5.4 N-methyl-isopicramic acid 5.0 N,N-di-(2-hydroxyethyl)-isopicramic acid 4.4

Isopicramic acid changed from bluish-red to orange-yellow, N-methyl-isopicramic acid changed from purple to pinkish-yellow, N,N-di-(2-hydroxyethyl)-isopicramic acid changed from claret to reddish-brown.

The colour change with N,N-di-(2-hydroxyethyl)-iso picramic acid was less distinct than with the other two dyestuffs. The results illustrated the superior fastness to acids of the dyestuffs employed in the process of this invention.

Experiments have shown that the acid-fastness of N- (Z-hydroxyethyl)-isopicramic acid is similar to that of N- methyl-isopicramic acid and inferior to N,N-di-(2-hydroxyethyl) -ispicramic acid.

What is claimed is:

1. A process of dyeing human hair which comprises applying to the hair an aqueous solution having a pH of from 2 to 9 of at least one direct dye of the formula:

OzN- N02 where:

M is selected from the class consisting of hydrogen, alkali and alkaline earth metals and ammonium and alkylammonium, hydroxyalkylammonium and aminoalkylammonium;

R is selected from the class consisting of alkyl having up to 6 carbon atoms and hydroxyalkyl having up to 4 carbon atoms; and

R is hydroxyalkyl having up to 4 carbon atoms.

2. A process as claimed in claim 1 in which R and R are both 2-hydroxyethyl.

3. A process as claimed in claim 1 in which M is selected from the group consisting of alkylammonium wherein the alkyl contains 1-6 carbon atoms and hydroxyalkylammonium and aminoalkylammonium wherein the alkyl contains 1-4 carbon atoms.

4. A composition for the direct dyeing of keratinous fibres, comprising an aqueous solution having a pH of from 2 to 9 of a compound of the formula:

O2N N02 where:

M is selected from the class consisting of hydrogen,

alkali and alkaline-earth metals and ammonium and alkylammonium, hydroxyalkylammonium and aminoalkylammonium;

R is selected from the class consisting of alkyl having up to 6 carbon atoms and hydroxyalkyl having up to 4 carbon atoms; and

R is hydroxyalkyl having up to 4 carbon atoms.

5. A composition as claimed in claim 4 in which R and R are both 2-hydroxyethyl.

6. A composition as claimed in claim 4 in which M is selected from the group consisting of alkylammonium wherein the alkyl contains 1-6 carbon atoms and hydro-xyalkylammonium and aminoalkylammonium wherein the alkyl contains 1-4 carbon atoms.

7. A compound having the formula OzN- NO:

where:

M is selected from the class consisting of alkali and alkaline-earth metals and ammonium and alkylammonium, hydroxyalkylammonium and aminoalkylammonium groups;

R is selected from the class consisting of alkyl having up to 6 carbon atoms and hydroxyalkyl having up to 4 carbon atoms; and

R is hydroxyalkyl having up to 4 carbon atoms.

8. A compound as claimed in claim 7 in which R and R are both 2-hydroxyethyl.

9. A compound as claimed in claim 7 in which M is selected from the group consisting of alkylammonium wherein the alkyl contains 1-6 carbon atoms and bydroxyalkylammonium and aminoalkylammonium wherein the alkyl contains 1-4 carbon atoms.

10. N,N-di-(2-hydroxyethyl)-isopicramic acid potassium salt.

11. N,N-di-(2-hydroxyethyl)-isopicramic acid ammonium salt.

12. N,N-di-(2hydroxyethyl)-isopicramic acid di-isobutylamine salt.

13. A process as claimed in claim 1 in which the aqueous solution also comprises a yellow dye selected from the class consisting of 2-nitro-N-methyl-N-acetyl-p-aminophenol and N-methyl-N-acetyl-isopicramic acid and alkali metal, alkaline-earth metal, ammonium and substituted-ammonium salts thereof.

14. A composition as claimed in claim 4 in which the aqueous solution also comprises a yellow dye selected from the class consisting of 2-nitro-N-methyl-N-acetyl-pamino-phenol and N-methyl-N-acetyl-isopicramic acid and alkali metal, alkaline-earth metal, ammonium and substituted-ammonium salts thereof.

15. A process as claimed in claim 1 in which the pH of the aqueous solution is from 6.5 to 7.5.

16. A composition as claimed in claim 4 in which the pH of the aqueous solution is from 6.5 to 7.5.

References Cited FOREIGN PATENTS 889,327 2/1962 Great Britain.

ALBERT T. MEYERS, Primary Examiner.

I. S. LEVITT, V. C. CLARKE, Assistant Examiners. 

1. A PROCESS OF DYEING HUMAN HAIR WHICH COMPRISES APPLYING TO THE HAIR AN AQUEOUS SOLUTION HAVING A PH OF FROM 2 TO 9 OF AT LEAST ONE DIRECT DYE OF THE FORMULA: 1,3-DI(O2N-),2-(M-O-),5-(R1-N(-R2)-)-BENZENE WHERE: M IS SELECTED FROM THE CLASS CONSISTING OF HYDROGEN ALKALI AND ALKALINE EARTH METALS AND AMMONIUM AND ALKYLAMMONIUM, HYDROXYALKYLAMMONIUM AND AMINOALKYLAMMONIUM; R1 IS SELECTED FROM THE CLASS CONSISTING OF ALKYL HAVING UP TO 6 CARBON ATOMS AND HYDROXYALKYL HAVING UP TO 4 CARBON ATOMS; AND R2 IS HYDROXYALKYL HAVING UP TO 4 CARBON ATOMS. 